• An aerial view of Old Faithful erupting taken from Observation Point with the Old Faithful Inn to the side.

    Yellowstone

    National Park ID,MT,WY

Hot Springs and How They Work

Emerald Spring glows green.

Emerald Spring

Hot springs with names like Morning Glory, Grand Prismatic, Abyss, Emerald, and Sapphire, glisten like jewels in a host of colors across the park's harsh volcanic plain. They are the most common hydrothermal features in the park.

Their plumbing has no constrictions. Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below. This circulation, called convection, prevents water from reaching the temperature needed to set off an eruption. [View the anatomy of a hot spring.]

Did You Know?

Summer Crowd at Old Faithful.

At peak summer levels, 3,500 employees work for Yellowstone National Park concessioners and about 800 work for the National Park Service.